Caracalla AE18, of Trajanopolis, Thrace.

Obv: (from top right) ANTWNEINOC PIOC AVGO, radiate, cuirassed bust right.
Rev: TRAIANOPOLEITWN, Flaming altar. 

Varbanov 2765

ebay sale 2005. Original seller information lost in website
attack, March 2009. Re-added in August, 2011